For the purpose of identifying specific products, or else for the purpose of data storage, in particular of small amounts of information, the prior art has widely disclosed the use of barcodes, for example one-dimensional or two-dimensional barcodes. By way of example, barcodes have been disclosed which are applied directly onto the products to be identified or marked, for example by means of appropriate printing techniques or else other techniques, for example laser techniques. However, as an alternative or in addition thereto, the barcodes can also be applied separately by means of appropriate adhesive techniques, for example by means of barcode labels.
Medical consumable articles are an important exemplary embodiment thereof; the present invention can, in particular, be related thereto but the present invention is not restricted thereto. Such medical consumable articles are used in medical diagnostics for example and can, for example, be embodied as disposable articles. Examples of such consumable articles are lancets for producing a puncture in an area of skin of a user, in particular for the purpose of generating a sample of a bodily fluid of the user. However, as an alternative or in addition thereto, the consumables can, for example, also comprise test elements, i.e. elements which are used to detect a property of a sample. By way of example, this property can be a concentration of one or more analytes in the bodily fluid. For this purpose, the consumables, which can for example be embodied as test strips, test tubes, test tapes or similar types of consumable articles, can in particular comprise one or more test fields. As a rule, these test fields comprise one or more test chemicals which specifically change at least one detectable property if the analyte to be detected is present. By way of example, this can be a property which can be detected electrochemically or optically, such as, for example, a color change. In principle, such test elements are known from the prior art. By way of example, these test elements can be used for qualitative and/or quantitative detection of blood glucose, lactate, cholesterol, coagulation values or similar parameters in the sample.
In the case of medical consumable articles, particularly in the field of medical diagnostics, at least one item of information in respect of the consumable article must, in general, be read into a medical instrument interacting with the consumable article. According to the prior art, this is generally performed manually or via electronic transmission methods, such as, for example, so-called ROM keys, which are added to packaging of the consumables and are entered into the medical instrument when the consumables are used for the first time. However, in principle, other forms of data transmission are also possible. By way of example, the transmitted data can contain information in respect of how the medical instrument interacts with the consumable articles and/or how the consumable articles are to be used. By way of example, this can be calibration information, batch-specific data or similar data since test strips, for example, usually have properties which differ from batch to batch and should be taken into account when using the consumable articles and more particularly when evaluating measured values which were obtained using these consumable articles.
The prior art has disclosed a number of different types of barcodes. Here, these can be simple one-dimensional barcodes, which are also referred to as linear barcodes, or, as an alternative or in addition thereto, else be multidimensional barcodes, for example so-called data matrix codes. Various options will be explained in more detail below.
Barcodes are usually read by means of hand-guided or motor-driven swipe systems or by means of moved mirror-deflected laser beams (scanners). Such reader systems are typically used in the case of one-dimensional barcodes. In the case of two-dimensional or multidimensional barcodes, which comprise significantly more information, use is generally made of camera systems or else mirror scanners. The use of CCD row-systems by moving the objects and goods past the CCD row in motor-driven and perpendicular fashion is also known, particularly in production processes and/or assembly-line methods. In order to decode and read out the information of these partial images of multidimensional barcodes, supplied by means of camera systems or, for example, CCD rows, high demands must generally be placed on both the motion sequence of the scanner or the moving past of the articles and on the utilized computer systems. In particular, use must generally be made of high-speed computer systems. In order to enable spatial resolution of the submodules, i.e. the binary information carriers, contained in the barcode, use is made of speed information contained in the code in the form of relative defined distances of the submodules in the case of one-dimensional barcodes or of clock tracks in the case of two-dimensional barcodes. Such barcodes are also referred to as “self-clocked barcodes”. However, all previously used barcodes assume a precise unidirectionality of the movement process, within the scope of which the article with the barcode is moved past the barcode reader. Although a violation of the unidirectionality is often identified in the case of one-dimensional barcodes, if such a so-called “bad scan” is identified, this generally requires a new scanning attempt. Mirror-guided or camera-supported scan systems in the case of two-dimensional barcodes often automatically ensure speed constancy and unidirectionality.
From prior disclosure it is known to provide a reader for moved-past transport goods or containers provided with a data medium. The reader comprises a reader head which can scan information present in an information track of the data medium. Provision is furthermore made for a clock track, which is scanned by means of two sensors. The two sensors are arranged offset with respect to one another. This arrangement can be used, inter alia, to identify a movement direction of the barcode and, accordingly, to read out information content into a shift register. See, e.g., EP 0 180 283 A2
It is also known to provide an apparatus for identifying objects moved along a track. By way of example, these can be transport cars which are provided with an information carrier. The information carrier comprises three rows of holes. Here, an upper row and a lower row serve as information rows, in which the encoded information is present. The upper and lower rows complement one another, and so respectively one hole is made in the holes of the rows lying above one another. By way of example, if the upper hole is present, this means that there is a 1 at this place of the binary number to be represented, while a hole in the lower row represents a 0. By contrast, the central row is embodied such that all holes are present therein, respectively independently of the respective information. The markings in the second row are arranged offset compared to the markings in the first and the third row. Respectively one row is associated with a scanning element which is arranged in a spatially fixed manner. Furthermore, a corresponding algorithm for identifying the information is described. Inter alia, edge identification is also disclosed herein. See, e.g., EP 0 379 017 A2.
It is also known to provide a test carrier analysis system for analyzing a constituent of a bodily fluid. Inter alia, provision is made in this case for a test carrier and a code carrier. See, e.g., EP 0 492 326 A2.
However, both motor-operated barcode readers and manually operated barcode readers can still lead to irregular conditions, in which the demands in respect of speed constancy and unidirectionality are violated. By way of example, mechanical resistances can occur in the case of motor-operated barcode readers and these may lead to jerks in the drive systems. If the transport direction is violated, bad scans can also occur in this case. Although manually operated barcode readers, in which the articles provided with the barcode are guided past the barcode reader manually, are comparatively stable with respect to speed constancy, a shaking operator of the system would, under certain circumstances, also fail to meet a demand in respect of unidirectionality.
It is therefore an object of the present invention to provide methods and devices which at least largely avoid the disadvantages of the above-described, known methods and de-vices. In particular, a barcode reader, in particular for use in a medical instrument, is to be proposed, which can be realized easily and with a small installation space and which can also be used reliably in manually guided applications.